| 摘要 |
A modulator architecture is disclosed for generating various waveforms, such as QPSK 8 PSK, 16 PSK, 16 QAM, 12/4 QAM, 32QAM and 64QAM. The modulator includes one or more biphase modulators, which are coupled to one or more QPSK modulators. Each of the bi-phase modulators includes a pair of switchable attenuators, for varying the degree of phase shift of the symbols, to form the various constellations. The architecture is expandable to generate higher order modulation formats. The architecture is also expandable to support non-linear predistortion.
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